{"id":"CVE-2026-84360","aliases":["EUVD-2026-97907","GHSA-vc32-4gwf-77xp","GO-2026-6799"],"status":"published","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools","description":"Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.","severity":{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.0042,"percentile":0.36804,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-288"],"published":"2026-10-12T21:08:04Z","modified":"2026-10-28T02:30:46Z","fixes":[{"ecosystem":"Go","package":"github.com/0xJacky/Nginx-UI","fixed_in":["1.9.10-0.20260703131214-23d1934099b0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/0xJacky/Nginx-UI","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.10-0.20260703131214-23d1934099b0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/0xJacky/Nginx-UI","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.9.10-0.20260703131214-23d1934099b0"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/0xJacky/Nginx-UI","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.9.10-0.20260703131214-23d1934099b0"}]}]}],"products":[{"vendor":"0xjacky","product":"nginx-ui"}],"references":[{"url":"https://github.com/0xJacky/nginx-ui/security/advisories/GHSA-vc32-4gwf-77xp","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/0xJacky/nginx-ui/commit/23d1934099b05b2a01589b48129dc3d3159d91c2","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/0xJacky/nginx-ui/releases/tag/v2.4.1","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84360","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-vc32-4gwf-77xp"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84360.json","tags":["advisory"]},{"url":"https://github.com/0xJacky/nginx-ui","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-84360","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools","description":"Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.","status":"published","published":"2026-10-12T21:08:04.687Z","modified":"2026-10-13T14:00:35.965Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:20:08.391556Z"}],"euvd":[{"id":"EUVD-2026-97907","description":"Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.","status":"published","published":"2026-10-12T21:08:04Z","modified":"2026-10-13T14:00:35Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"updated_at":"2026-11-02T17:27:20.758283Z"}],"ghsa":[{"id":"GHSA-vc32-4gwf-77xp","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools","description":"### Summary\nAn OTP-enabled authenticated user who cannot use the HTTP configuration mutation endpoints without a valid secure session can still mutate Nginx configuration through `/mcp` and `/mcp_message` using only ordinary authentication.\n\n### Details\nThe HTTP configuration mutation surface is explicitly grouped behind `middleware.RequireSecureSession()`. By contrast, the MCP endpoints are exposed with only `middleware.AuthRequired()`. The MCP server exposes configuration mutation tools including `nginx_config_add` and `nginx_config_modify`, so OTP-enabled users gain an alternate path around the intended step-up requirement.\n\nRelevant code paths:\n- [api/config/router.go](/home/kali/Desktop/bounty/nginx-ui/api/config/router.go:14)\n- [internal/middleware/secure_session.go](/home/kali/Desktop/bounty/nginx-ui/internal/middleware/secure_session.go:52)\n- [mcp/router.go](/home/kali/Desktop/bounty/nginx-ui/mcp/router.go:9)\n- [mcp/config/config_add.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_add.go:34)\n- [mcp/config/config_modify.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_modify.go:55)\n\nThis is a security-control bypass rather than a missing feature. The product already established that OTP-enabled users should complete a secure session before high-impact configuration mutations are accepted on the HTTP path.\n\n### PoC\nI verified this locally in an isolated environment with a temporary end-to-end harness that exercised the real `/mcp` and `/mcp_message` routes.\n\nWhat the executed test did:\n1. Created a temporary config directory and configured Nginx control commands to harmless local values (`true`) to avoid touching the host.\n2. Created a real OTP-enabled user in a temporary SQLite database.\n3. Generated a real JWT for that OTP-enabled user.\n4. Started a local test server exposing the real `/mcp` and `/mcp_message` routes.\n5. Opened an authenticated SSE connection to `/mcp` with the JWT and no `X-Secure-Session-ID`.\n6. Initialized the MCP session over `/mcp_message`.\n7. Called the real `nginx_config_add` tool over `/mcp_message`.\n8. Verified that the tool succeeded and created `mcp-bypass.conf` in the managed config directory without any secure-session step-up.\n\nObserved result from the actual local verification:\n- The MCP session initialized successfully without any `X-Secure-Session-ID`.\n- The config file was written through the MCP tool path using only JWT authentication.\n\n### Impact\nOTP-enabled accounts lose the intended step-up protection for high-impact Nginx configuration changes when MCP is enabled. A user who should be blocked until re-authenticating can still create or modify configuration files and trigger reload behavior through MCP.","status":"published","published":"2026-10-15T20:14:10Z","modified":"2026-10-15T20:14:11Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:41:32.483482Z"}],"nvd":[{"id":"CVE-2026-84360","description":"Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.","status":"published","published":"2026-10-12T21:17:22.96Z","modified":"2026-10-13T14:31:20.75Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T14:12:56.72789Z"}],"osv":[{"id":"CVE-2026-84360","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools","description":"Nginx UI is a web user interface for the Nginx web server. Prior to 2.4.1, the HTTP configuration mutation routes require RequireSecureSession, but /mcp and /mcp_message require only ordinary authentication before exposing nginx_config_add and nginx_config_modify. An OTP-enabled user with a normal JWT but no valid X-Secure-Session-ID can therefore create or modify Nginx configuration and trigger reload behavior through MCP, bypassing the intended step-up control. This issue is fixed in version 2.4.1.","status":"published","published":"2026-10-12T21:08:04.687Z","modified":"2026-10-28T02:30:46.219630693Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T15:45:18.482949Z"},{"id":"GHSA-vc32-4gwf-77xp","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools","description":"### Summary\nAn OTP-enabled authenticated user who cannot use the HTTP configuration mutation endpoints without a valid secure session can still mutate Nginx configuration through `/mcp` and `/mcp_message` using only ordinary authentication.\n\n### Details\nThe HTTP configuration mutation surface is explicitly grouped behind `middleware.RequireSecureSession()`. By contrast, the MCP endpoints are exposed with only `middleware.AuthRequired()`. The MCP server exposes configuration mutation tools including `nginx_config_add` and `nginx_config_modify`, so OTP-enabled users gain an alternate path around the intended step-up requirement.\n\nRelevant code paths:\n- [api/config/router.go](/home/kali/Desktop/bounty/nginx-ui/api/config/router.go:14)\n- [internal/middleware/secure_session.go](/home/kali/Desktop/bounty/nginx-ui/internal/middleware/secure_session.go:52)\n- [mcp/router.go](/home/kali/Desktop/bounty/nginx-ui/mcp/router.go:9)\n- [mcp/config/config_add.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_add.go:34)\n- [mcp/config/config_modify.go](/home/kali/Desktop/bounty/nginx-ui/mcp/config/config_modify.go:55)\n\nThis is a security-control bypass rather than a missing feature. The product already established that OTP-enabled users should complete a secure session before high-impact configuration mutations are accepted on the HTTP path.\n\n### PoC\nI verified this locally in an isolated environment with a temporary end-to-end harness that exercised the real `/mcp` and `/mcp_message` routes.\n\nWhat the executed test did:\n1. Created a temporary config directory and configured Nginx control commands to harmless local values (`true`) to avoid touching the host.\n2. Created a real OTP-enabled user in a temporary SQLite database.\n3. Generated a real JWT for that OTP-enabled user.\n4. Started a local test server exposing the real `/mcp` and `/mcp_message` routes.\n5. Opened an authenticated SSE connection to `/mcp` with the JWT and no `X-Secure-Session-ID`.\n6. Initialized the MCP session over `/mcp_message`.\n7. Called the real `nginx_config_add` tool over `/mcp_message`.\n8. Verified that the tool succeeded and created `mcp-bypass.conf` in the managed config directory without any secure-session step-up.\n\nObserved result from the actual local verification:\n- The MCP session initialized successfully without any `X-Secure-Session-ID`.\n- The config file was written through the MCP tool path using only JWT authentication.\n\n### Impact\nOTP-enabled accounts lose the intended step-up protection for high-impact Nginx configuration changes when MCP is enabled. A user who should be blocked until re-authenticating can still create or modify configuration files and trigger reload behavior through MCP.","status":"published","published":"2026-10-15T20:14:10Z","modified":"2026-10-19T21:41:02.724775704Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","level":"high"}],"cwes":["CWE-288"],"updated_at":"2026-11-02T15:46:56.981655Z"},{"id":"GO-2026-6799","title":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools in github.com/0xJacky/Nginx-UI","description":"Nginx UI: OTP secure-session step-up can be bypassed via MCP configuration tools in github.com/0xJacky/Nginx-UI","status":"published","published":"2026-10-19T21:08:35Z","modified":"2026-10-19T21:31:53.417011797Z","updated_at":"2026-11-02T15:47:03.11707Z"}]}}